Empty Block

An empty block is a fully valid Bitcoin block that includes only its coinbase transaction and no user transactions — even though the mempool is typically full of fee-paying transactions waiting to be confirmed. The miner still earns the block subsidy, but forgoes the transaction fees it could have collected by including a full block of transactions.

Why empty blocks happen

Empty blocks are usually a byproduct of timing, not laziness. The moment a competitor finds a block, every other miner is racing to build on top of it. A pool can begin hashing the next block the instant it learns the new block's header, before it has fully downloaded and validated the block's transactions. During those first seconds it has no verified transaction set to include, so it mines an empty candidate. This practice is closely tied to SPV (validationless) mining, where work begins from the header alone.

The economics and the decline

The trade-off is direct: an empty block sacrifices fee revenue to shave precious milliseconds off the race and reduce the risk of being orphaned. As block propagation and validation got faster — notably improvements around Bitcoin Core 0.12 and compact-block relay — the window in which empty mining made sense shrank, and the share of empty blocks fell sharply across the network.

Empty blocks reduce effective transaction throughput, which matters when the mempool is congested and fees are high. The phenomenon connects directly to block propagation speed and a miner's incentive to minimize orphan risk while a new block spreads across the network.